Category Archives: Children and Nature

The Invasion of Lake Joy

Lake Joy

Two boys next to lake covered with waterlily

Sgian and Aeden Peterson fight the battle against fragrant water lily.
Photo by Amy Peterson

Lake Joy is a community of single family homes and summer cabins nestled halfway between the towns of Carnation and Duvall in western Washington State. Bald eagles, great blue herons, kingfishers, river otters, deer, black bears, the occasional cougar, bats, and owls live here. Many migratory waterfowl come through in the fall and spring.

Red and orange sunsets make way for starlit nights. The lake calls you to explore its calm, clear waters in kayaks, canoes, or paddle boards, and it is refreshingly crisp for a swim on a hot August afternoon. Public access is limited to a narrow trail where small boats can be hand-carried in. Homeowners around the lake take care of it and are proud of their neighborhood.

If you live in the Lake Joy community you better have a bit of the pioneering spirit. You have to be self sufficient because you are fifteen minutes’ drive from the nearest grocery store or fire station. You need to plan ahead and stock up for when the power goes out or you are stranded due to flooding. In this rural area, most homes have chainsaws, tractors, and generators.

Despite the independent self-sufficiency that we are so proud of, our neighborhood has a strong sense of community spirit. Neighbors watch out for each other. We do many things as a community to help ourselves. We hold meetings to discuss what is happening in our area, we throw parties to get to know one another, and we work together to solve problems. One problem we are trying to solve is the threat to biodiversity in our lake due to invasive species.

Shifting Balance

Aerial view of Lake Joy

Lake Joy and its watershed
Photo: King County

When my family first arrived at Lake Joy in 2012, I wanted to learn about its history and natural history. I called Dave Smith, who has lived on Lake Joy for over thirty years and serves as president of the Lake Joy Community Club.

Dave shared his knowledge with me about the history, health, and food web of the lake. One story he shared was from the 1950’s, when the lake was regularly stocked with trout for fishermen.

Dave told me that one season, the lake was accidentally stocked with trout that were diseased. The entire lake was then poisoned to kill all of the diseased fish. Fish coming in through the five streams that drain into the lake eventually repopulated it. Brown bullhead became the dominant species. Brown bullhead are a catfish introduced from the eastern United State, and they are not native to Washington.

Shortly after that, however, river otters moved in to feed on the overpopulating brown bullhead. Now the lake has more balance in its fish populations. Many different fish species live in the lake, including cutthroat trout, kokanee salmon, and bass.


Massive stand of knotweed above a body of water

Knotweed in King County
Photo by King County

When my family moved to Lake Joy in 2012, our sons immediately found the nearby stands of dense “bamboo” to be a living armory. It provided an endless supply of swords and spears for their lake-front battles. However, once we found out that they were using the ammunition of the invasive species Japanese knotweed (Polygonum cuspidatum), we called a complete cease fire.

Japanese knotweed was introduced an ornamental to the United States in the 1870’s. A perennial, it spreads quickly when its rhizomes and fragments of roots and stems are distributed in aquatic ecosystems. Its colonies disrupt plant communities and prevent native plants from thriving. Infested areas can have ten times fewer plant species living in them than areas without knotweed. Knotweed is so vigorous it can grow through concrete, and its growth can cause damage to wells and septic systems.

Knotweed quickly changes the look and processes of an ecosystem. Few insects feed on it and it has few diseases. This hardiness is one of the reasons it invades new areas so well.

Another plant we admired at first in our new home was the fragrant water lily (Nymphaea odorata). This aquatic plant has floating leaves and grows in water up to six feet deep. The flowers are large, showy, and usually white in color, blooming from June to October. After pollination, the stalk pulls the fertilized flower under the water. Found in freshwater lakes and ponds, fragrant water lily spreads by floating seeds and rhizomes. Water lily is usually spread into new areas by people with boats, although ducks, geese, and other animals also carry it from lake to lake.

We soon learned that this plant also out-competes native plants and changes the food web in a body of water. Fragrant water lily’s growth habit and density create areas of low oxygen under the lily pads, increase water temperature, and increase habitat for mosquitoes. When the leaves die back, algae increases and dissolved oxygen decreases.

Fragrant water lily can grow so densely that it can prevent people and boats from entering a body of water. And, on a more sinister level, it can drown people who get tangled in the stalks.

We were pleased, however, to discover a new predator at Lake Joy that is causing decreases in the populations of both Japanese knotweed and fragrant water lily!

Our new predator? The residents of Lake Joy.

Community Takes Action

waterlily covering the surface of a lake

Fragrant waterlily from a canoe.
Photo: King County

As part of my master’s program with Miami University’s Project Dragonfly and the Woodland Park Zoo, I prepared a presentation and led an invasive species mapping exercise for the Lake Joy community. In response, the Lake Joy community decided to eradicate these aquatic invasive species, with a focus on organic methods of removal. We formed work parties specifically to get rid of them.

During the spring and summer of 2014 many Lake Joy residents went out in boats and collected fragrant water lily stalks and leaves. Fragrant water lily is controlled by pulling the leaves throughout the growing season; this starves the plant.

Manual removal is most effective in May when the leaves begin to come out. We picked the leaves and then pulled them completely out of the water to be composted because the plant can only live in an aquatic setting.

Permits are generally required for any control methods done in natural waterbodies such as lakes and wetlands, including manual methods. Further information about how to remove fragrant water lily from lakes can be found in the Washington Department of Fish and Wildlife’s pamphlet, Aquatic Plants and Fish.

Because so many parts of Lake Joy are infested with water lily, it is a long process. This past spring, I again saw neighbors out in boats, pulling leaves near their property.

Our neighborhood also took on the Japanese knotweed: we pulled it, burned it, covered it with black plastic, or injected it with glyphosate (Round-Up). Due to knotweed’s hardy nature and its method of reproduction, limited organic options exist short of pulling up its dense root ball. Knotweed can be effectively controlled with glyphosate because the chemical is sent to the rhizomes to prevent new plants. But knotweed is so vigorous that it cannot be composted. Discarded stalks will form roots and create new infestations. Knotweed either needs to be burned or put in trash bags to be hauled away with the garbage pickup.

This past spring brought new growth of both fragrant water lily and Japanese knotweed. To prevent re-infestation, we need to continue to act together to remove these invasive plants and add native plants to fill in the void. The lake will require annual follow up to get rid of all plants and prevent them from returning.

The natural beauty of Lake Joy is what draws people to it. We are fortunate to live in an area that has a strong sense of community and a willingness to work together to solve problems. Our neighborhood knows that we will have to work hard to sustain Lake Joy and our community.

More Information

For more information on these invasive plants and others, King County offers fact sheets, videos, classes, and links to resources.

Fragrant water lily

Japanese knotweed

Amy Peterson lives on Lake Joy with her family. She developed this article from a project on community involvement in conservation. She is a masters student with Miami University’s Project Dragonfly and the Woodland Park Zoo, in the Advanced Inquiry Program. She will graduate in December 2015.